GB2069192A - Programmable timed control arrangements - Google Patents

Abstract

In a programmable controller Figure 2 for timed control of appliances, eg in a central heating system, the beginning and end of one period of operation of an appliance, eg a radiator, are set up by potentiometer sliders 4, 6 respectively; the setting of sliders 5, 7 define another operational period. Potentiometers 9, 10 are provided for setting desired temperatures. The analog time signals from the sliders are converted to digital signals at converter 22 for comparison at 23 with digital time signals from a master clock. Upon correspondance, a control signal is delivered to a line 25 and the next slider tapping is selected for coupling to the comparator 23. One such controller may be provided for each radiator or heater in the system, the master clock time signal being transmitted to all of the controllers. <IMAGE>

Description

SPECIFICATION Programmable time controller This invention relates to a programmable time controller and particularly but not exclusively to a controller for time controlling a heating appliance.

In a known heating system, in which heat is supplied to a number of rooms by means of a heating appliance in each room a single programmable controller is usually provided including a time clock which may be set by means of a number of mechanical trip switches, to turn ON and turn OFF the heating applicances at preselected times.

In the case of pumped, water filled radiator systems, a water pump will be controlled by the time clock whilst in the case of electrical applicances, the supply of electrical current is controlled.

A problem with the known system is that it is often not required or desirable to have all rooms heated during the same periods of time. For example in a domestic environment bedrooms and the lounge ideally require to be heated at different times.

Bedrooms need to be heated for a short period each morning whilst it is often unnecessary to heat the lounge during this early morning period.

In presently known systems, in order to apply heating to selected rooms at individually selected times, an individual controller including a time clock together with programmable trip switches would need to be associated with each heating appliance.

Using the above described known programmer for this purpose would result in an expensive heating system. In addition each time clock would need to be manually reset following an electrical power failure.

This invention seeks to provide a programmable time controller suitable for controlling an energy dissipating appliance in which the above mentioned problems are mitigated.

According to this invention there is provided a programmable time controller for time controlling an energy dissipating appliance with which it is associated, the controller including presettable time selector means for providing electrical signals indicative of desired times of at least two boundaries, each between periods of differing operating conditions of the appliance; and a comparator for comparing the electrical signals with a signal derived from a master time clock, an output signal provided by the comparator being utilised to control the operation of the appliance.

The energy dissipating appliance may be a heating appliance.

The heating appliance may be an electrical appliance which dissipates energy by being electrically heated or may be a liquid filled pumped radiator which dissipates energy by having pre-heated liquid pumped therethrough.

The time selector means may include a plurality of time selectors each for setting at least one time of commencement of an operating condition of the appliance associated with that time selector.

The presettable time selector means may inlude a potentiometer the electrical signals being derived from at least one adjustable tapping on the potentiometer.

A plurality of potentiometers may be provided each potentiometer having one or more adjustable tappings for setting the commencement time for an operating condition of the appliance associated with the respective potentiometer.

The or each potentiometer may have one or more tappings each being adjustable by means of a respective linearly moveable slider.

The comparator may be a digital comparator, the said electrical signals being fed to the comparator in digital form.

An analogue-to-digital converter may be provided for converting analogue signals provided by each potentiometer tapping into digital form.

The controller may include presettable temperature selector means for providing electrical signals indicative of a desired temperature setting of the environment in which the heating appliance is located.

The presettable temperature selector means may be operable for preselecting a plurality of temperatures for operation during respective time periods in dependance upon the setting of the time selector means.

The temperature selector means may include one or more further potentiometers the electrical signals being derived from one or more adjustable tappings.

In order to preselect a plurality of temperatures each applicable during a respective time period controlled by the time selector means a plurality of further potentiometers may be provided each having an adjustable tapping for selecting the respective temperature.

Each further potentiometer may have a linearly movable slider for adjusting the tapping point on the potentiometer.

One or more indicators may be provided to indicate whether the environment has reached a temperature set by the temperature selector means.

An exemplary embodiment of the invention will now be described with reference to the drawings in which: Figure 1 is a front panel view of a programmable time controller in accordance with the invention; and, Figure 2 shows a functional block diagram of the controller illustrated in Figure 1.

Referring to Figure 1 the programmable time controller has a housing 1 and presettable time selectors in the form of linear movement potentiometers 2 and 3. The potentiometer 2 has two adjustable tappings which are controlled by sliders 4 and 5 whilst the potentiometer 3 also has two tappings controlled by sliders 6 and 7. The potentiometer sliders 4, 5, 6, and 7 which control the various adjustable tappings of the potentiometers 2 and 3 move adjacent a 24 hour time scale 8.

The potentiometers 2 and 3 are used to set the times of commencement of differing operational conditions of an energy dissipating appliance with which the controller is associated. The controller is particularly suitable as a controller for a heating appliance e.g. a radiator forming part of a central heating system. The potentiometer 2 is used to set the desired commencement time for periods in which the heater is required to heat the environment in which it is located to a relatively high temperature, whilst the potentiometer 3 is utilized to set the commencement of time periods in which the heater is required to operate at a lower temperature level.

The sliders 4,5,6, and 7 set the adjustable tappings on the potentiometers 2 and 3 and these tappings provide electrical potentials which are representative of the position of the tappings along the potentiometers and therefore of the positions along the 24 hour time scales against which the sliders are aligned.

These electrical potentials are therefore also representative of the times indicated by the sliders. The slider 4 will be representative of a time at which the controlled heater will heat up its environment to a relatively high temperature whilst the slider 6 will mark the time boundary at which the heater changes over from heating its environment to a relatively high temperature to a relatively low temperature heating requirement.

The slider 5 marks the beginning of a further high temperature period whilst the slider 7 marks a return to the lower temperature condition.

The electrical potentials provided by the tappings set by the sliders 4,5,6 and 7, are utilized as described later to provide electrical signals to bring into effect the conditions indicated by those sliders at the appropriate times.

A further two potentiometers 9 and 10 are provided and these are respectively used to set the temperatures during the periods set by the sliders of the potentiometers 2 and 3. The potentiometers 9 and 10 are also linear movement potentiometers provided with sliders 11 and 12, which control respectable adjustable tappings and which move adjacent to a linear temperature scale 13.

In a 24 hour cycle of operations the controller will first of all operate at a time indicated by the slider 4 to cause the heating appliance, with which the controller is associated, to heat the environment, in which it is located, to the high temperature setting indicated by the slider 11 on the potentiometer 9.

The next event in time is indicated by the slider 6 which indicates the start time for a relatively low temperature period and when the time indicated by this slider 6 is reached the heater will only heat its environment to the temperature indicated by the slider 12 on the relatively low temperature potentiometer 10. This condition can effectively be made an OFF condition by setting the slider 12 to a temperature which is below the ambient temperature of the environment in which the heater is situated. At the time indicated by the slider 5 the heater will once again heat upto the relatively high temperature whilst at the time indicated by the slider 7 the low temperature condition will once again be assumed.

The temperature setting potentiometers 9 and 10 have located beneath them indicating lights 14 and 15 respectively which are used to indicate which temperature setting is in effect at any particular time.

Afurtherthree indicating lights 16, 17, and 18 are provided which respectively indicate whether the environment temperature is above equal to or less than the temperature set on the setting potentiometer 9 or 10 which has effect at any particular time.

The controller also incorporates a programme advance button 19 operation of which causes the particular programme currently being effected to be advanced to the programme indicated by the next time selector slider 4, 5, 6 or 7 in the sequence as later described.

Operation of the controller will now be described more fully with reference to Figure 2 in which like parts to those shown in Figure 1 bear like reference numerals.

The potentiometer tappings set by the sliders 4, 5, 6, and 7, on the potentiometers 2 and 3 are fed to a demultiplexing unit 20 which selects the electrical potential from one of the tappings under the control ofa control unit 21.

The potential from the selected tapping is fed to an analogue-digital convertor which feeds a digital signal representative of the analogue electrical potential obtained from the selected tapping to one input of a digital comparator 23 the other input of which receives a digital signal from a master clock, this master clock signal being representative of true time.

When the digital signals fed to the comparator from the analogue-digital convertor 22 and the master clock are equal, the comparator 23 provides an output on a signal line 24 which is fed via the control unit 21 to an output line 25. The control unit 21 is also coupled to the demultiplexer 20 via line 26 and when the control unit 21 receives an output signal from the comparator 23 over the line 24 the control unit causes the demultiplexer to select the next potentiometer tapping in the time sequence. In this particular case the tapping set by the slider 4 will be the first tapping selected and this will be followed in turn by those set by the sliders 6, 5, and 7.

The output signal obtained from the comparator 23 on the line 24 and fed to the output line 25 is used as an enable signal to enable the heater to dissipate energy either by having electrical power applied directly to it in the case of an electrical heater or by having water pumped therethrough in the case of a pumped water filled radiator. The energy dissipation will of course be subject to further control in dependence upon temperature setting. In the latter case of a pumped radiator the enable signal provided on the line 25 may be used to enable the opening and closing of a valve in the water supply to the particular heater with which the controller is associated.

The tappings set by the sliders 11 and 12 on the potentiometers 9 and 10 respectively are also coupled to a further demultiplexer 27 which selects one of the tappings and feeds the electrical potential obtained therefrom to a further analogue to digital converter 38 which provides a digital output signal at 29 which is also utilized to effect temperature control of the heater. The demultiplexer 27 is also coupled to the control unit 21 over a control line 30 which causes the demultiplexer 27 to select sequentially the next tapping on the potentiometers 9 and 10 each time an output signal is obtained from the comparator 23.

The control unit 21 also has an input line 31 fed from the advance button 19. A signal on the line 31 causes the demultiplexer 20 to select the next slider in sequence to advance the programme.

The use of the controller in accordance with this invention provides significant advantages over currently known programmable controllers particularly in the field of central heating. The controller does not include an individual time clock but includes a time selector which provides electrical signals which are representative of an event in the programme sequence. In the embodiment described in the drawings the time selection is effected by means of potentiometers with adjustable slidertappings. The controllertherefore generates non-volatile electrical signals which are representative of the time of occurrance of a programmed event. This means that should electrical power fail and then be restored the time representative electrical signals will also be restored to their orginal values and no resetting of the controller itself is required.The only component which needs resetting after a power failure is the master clock which does not need to form part of the controller but merely provides a time representative signal input to the controller.

Since the controller does not need to incorporate a clock it can be made relatively simple in construction and cheaply and it is therefore quite practical to use a separate programmable controller in association with each heater of a central heating system. The heaters in different rooms can therefore be individually controlled to suit the particular usage of the rooms so that no room is heated unnecessarily when it is not required to be occupied.

Each controller is provided with a master clock signal input from a single master clock and therefore all the programmers are synchronised to the same time standard. Following a power failure it is only necessary to reset the single master clock in order to synchronise the entire central heating system to real time. In addition by providing temperature selectors on each programmable controller it is possible to set the temperature required in each room to an individual value to suit the needs of that room.

The invention therefore provides the means of obtaining a completely flexible heating system without any unnecessary duplication of expensive components such as time clocks each of which might require resetting in the event of a power failure.

Although the invention has been particularly described with reference to the control of heating appliances in a central heating system this is not essential and the controller maybe utilized to time control any process in which energy is dissipated.

Modifications may also be made to the described embodiment without departing from the scope of this invention. For example it is not essential that the time and temperature selectors be provided in the form of potentiometers but any suitable means may be utilized for producing non-volatile electrical signals representative of time and/or temperature.

Claims (14)

1. A Programmable Time Controllerfortime controlling an energy dissipating appliance with which it is associated, the controller including presettable time selector means for providing electrical signals indicative of desired times of at least two boundaries each between periods of differing operating conditions of the appliance and a comparator for comparing the electrical signals with a signal derived from a mastertime clock an output signal provided by the comparator being utilised to control the operation of the appliance.

2. A programmable time controller as claimed in Claim 1 in which the time selector means includes a plurality of time selectors each for setting at least one time of commencement of an operating condition of the appliance associated with that time selector.

3. A programmable time controller as claimed in Claim 1 or 2 in which the presettable time selector means includes a potentiometer the electrical signals being derived from at least one adjustable tapping on the potentiometer.

4. A programmable time controller as claimed in Claim 3 in which a plurality of potentiometers is provided each potentiometer having one or more adjustable tappings for setting the commencement time for an operating condition of the appliance associated with the respective potentiometer.

5. A programmable time controller as claimed in Claim 3 or 4 in which the or each potentiometer has one or more tappings each being adjustable by means of a respective linearly moveable slider.

6. A programmable time controller as claimed in any preceding claim in which the comparator is a digital comparator the said electrical signals being fed to the comparator in digital form.

7. A programmable time controller as claimed in Claim 6 in which an analogue-to-digital converter is provided for converting analogue signals provided by each potentiometer tapping into digital form.

8. A programmable time controller as claimed in any preceding claim and further including presettable temperature selector means for providing electrical signals indicative of a desired temperature setting of the environment in which the heating appliance is located.

9. A programmable time controller as claimed in Claim 8 in which the presettable temperature selector means is operable for preselecting a plurality of temperatures for operation during respective time periods in dependance upon the setting of the time selector means.

10. A programmable time controller as claimed in Claim 8 or 9 in which the temperature selector means includes one or more further potentiometers the electrical signals being derived from one or more adjustable tappings.

11. A programmable time controller as claimed in Claim 10 in which in order to preselect a plurality of temperatures each applicable during a respective time period controlled by the time selector means a plurality of further potentiometers is provided each having an adjustable tapping for selecting the respective temperature.

12. A programmable time controller as claimed in Claim 11 in which each further potentiometer has a linearly moveable slider for adjusting the tapping point on the potentiometer.

13. A programmable time controller as claimed in any one of Claims 8 to 12 in which one or more indicators are provided to indicate whether the environment has reached a temperature set by the temperature selector means.

14. A programmable time controller substantially as herein described with reference to and as illustrated in Figures 1 and 2 of the drawings.